Close the window of the condominium stairwell to make a veranda? The Supreme Court says no

The story

The story arose when a condominium was suing a company, owner of an apartment with a terrace overlooking the stairwell. The defendant had in fact created a veranda by infilling its own terrace, incorporating within it a condominium window located on the first floor landing. That opening, although modest, guaranteed light and air to the stairwell. With the closure, the window was rendered unusable and its maneuverability depended exclusively on the owner of the veranda, who could decide whether and when to open the external shutter or the small upper transom.

The Court, after having carried out witness testimony and technical advice, accepted the condominium’s request, ordering the removal of the infill in the part in which it incorporated the opening. According to the judge, the intervention had significantly reduced the lighting function and almost completely the ventilation function, violating the articles. 1102 and 1122 cc The company appealed the first instance sentence.

The Court of Appeal confirmed the decision in its entirety, noting that the incorporation of an open and ventilated space into a closed environment inevitably involves a subtraction of light and air from the stairwell, regardless of the characteristics of the frame. Furthermore, the possibility of opening or closing the shutter was left to the exclusive discretion of the condominium owner who had built the veranda, with evident prejudice to the community.

The company then appealed to the Court of Cassation, complaining of violation of the articles. 1102, 1120 and 1122 cc, apparent motivation and failure to examine decisive facts, in particular the previous use of the opening and its limited usefulness.

The decision of the Supreme Court

The Supreme Court, with order no. 7671 of 30 March 2026, rejected the appeal and fully confirmed the assessments of the judges of merit. The Court highlighted principles of fundamental importance in condominium matters: when a condominium owner carries out works on his exclusive property that affect common goods, it is always necessary to verify compliance with the limits imposed by the art. 1102 cc; no one can alter the destination or usability of the common thing without the consent of the other participants; and, above all, the openings intended to guarantee light and air to the common areas cannot be closed, incorporated or made unusable, because this involves a substantial modification of the common good and takes away utility from the other condominiums.

The Court of Cassation also underlined that the evaluation of the concrete prejudice (i.e. whether the work carried out has an appreciable impact on the usability of the common good) is left to the judge of merit. Once this evaluation has been carried out in a logical and coherent way, it cannot be revised in terms of legitimacy. In the specific case, the judges of first and second degree had ascertained, on the basis of the preliminary findings and technical advice, that the incorporation of the window had effectively reduced light and air in the stairwell, making their use dependent on the will of the individual owner.

Hence the confirmation of the restoration order: incorporating a condominium opening into a private veranda is never permitted, because it deprives the other condominiums of an essential utility and alters the functional balance of the building.

Concluding considerations

The Supreme Court’s decision highlighted how the individual cannot close a condominium opening by means of supported or attached constructions, since such an intervention alters the material consistency of the common good and compromises its function.

It does not point out that the opening is small, difficult to maneuver or rarely used: what matters is its objective purpose of serving the stairwell, guaranteeing a minimum of lighting and ventilation. If the damage (darkening of the stairs) derives from the concurrent conduct of several parties, each is responsible for the illicit behaviour.

According to the supreme judges, even on the subject of condominium relationships, one or the other of the authors can be called to respond indifferently for the illicit act of a condominium owner which is added to the illicit act of another condominium owner with respect to the common property, without having to take into account the priority in the commission of the act (Cass. Civ., section II, 26/06/2025, n. 17237).